Automatic scaffolding machine



Sept. 29, 1959 A. R. HOWARD AUTOMATIC SCAFFOLDING MACHINE 4 Sheets-Sheet l Filed Jan. l1, 1957 Sept- 29, 19.59 A. R. HOWARD 2,90?365 AUTOMATIC SCAFFOLDING vMACHINE Filed Jan. 11. 1957 4 Sheelzs-Sl'xeeiI 2 v i w ,M-l H.

IN1/EN T01@ Q Sept. 29, 1959 A. R. HOWARD AUTOMATIC scAFFoLDING MACHINE 4 Sheets-Sheet 3 Filed Jan. 11, 1957 INVENTOR.

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United States Patent'.

AUTOMATIC .SCAFFOLDING MACHINE Arthur R. Howard, Fontana, Calif.

.ApplicationilanuarylL 1957, Serial No. 633,689

6 Claims. (Cl. ISI-136) This inventionrelatesto scaiolds,v andature-particularlylto -a scaoldraising `and lowering-mechanismlfor-use on chimneys and similar structures.

The main l'object ofthe invention isto Aprovide anov'el and improved vautomatic self-'elevating scaffold apparatus `Vfor use on chimneys -or `the like, said aparatus 'being -simple ,fin-constructionl being'easy tov install Von a structure, and

eliminating a great deal off-the laborandhazard usually involved inlthe maintenance 4and repair of chimneys and similar structures.v

A further object of the invention is to provide an improved-*automatic selfelevating scaffold apparatus for use ontfchimneys orthelike, said aparatus involving'inexpen- -sive` components',': being reliable in operation, and-'provid- -ing access'to tall structures, such as chimneys or the like,

without requiring the use of expensive au-xiliary equipm'cnt, such Aas cranes, ladders, orthe like.

Further'objects and advantages of the invention will become apparent froml the following description and claims, and 'from the accompanying drawings, wherein:

Figures-1 -is a-horizontal cross sectional lview taken ythrough' a=chimney on which is mounted animproved automatic scaffold apparatus constructed'in'accordance "with the present invention.

Figure-2 is an enlarged'elevationalviewofth'e main support Vemployed inthe scalold apparatus 'of Figure 1,

and -ofA parts of the'l scaffold cooperating vwith said A'main support.-y

F'igure 3 is anl enlarged transverse-vertical cross sectional View taken on the line"3"-3 of Figure "1.

Figure 4-is Va'vertic'al cross sectionallview taken 'on-'the line 4-4 of FigureB.

"Figure 5 is an enlarged fragmentaryplandetail view vure 9.

Figure 9 is an enlarged vertical cross sectional view taken on` the line` 9*-9 of Figure 2'.

Figure 10 is a horizontal cross sectional view taken on the line 10-10 of FigureS.

lFigure 11 is an enlarged horizontal' cross sectionalL view taken on the'line 11-11 of Figure 2.l

Figure 12'is a verticalcross sectional viewlftaken` on the line 12-12 of Figure 11.

Figure 13is' across sectional detail view-taken on the line 13--13 of Figure 12.

Figure 14' is an enlarged cross sectional view taken lon the line'14-14'of Figurel,

Figure l5' is an enlarged top view of 'the"railing`jguides land the 'post member employed in the automatic 'scalold *apparatus ofFigure"1,- and showniin' Figure14'.'

ICC

Figure 15a is .a fragmentary elevational view -taken "on theline 15a-15a ofrFigure 15;

:Figure 16 is an enlarged: horizontal cross sectional/view taken onthe line16'16 of Figure 4.

Figure 17 isa fragmentary horizontal-cross sectional 'View similar to .the upper portion of."Figure 48, but showing a modified form ofthe 'automatic scaiold. apparatusfof lthe ypresent invention.

Figure 18 is a vertical cross sectional view taken through one of the jack cylinders of the automatic scaffold apparatus of Figure 17.

Figure 19 is a vertical crosssectional view, partlylin elevation, taken through one of the jack cylinders associ- .ated with an auxiliary support of the fonnof automatic zscaiold apparatus of Figures 17 and 18.

vFigure v20 is aschematic diagram illustrating afurther m'o'diticationz of automatic scaffold apparatus according to the present invention, wherein each of the scaiold-elevatingplungers is driven by aseparateelectric motor and fwherein the motors are connected in a series circuit for .energizing and simultaneously controllingsame.

Referringl to the drawings, and more particularly lto Figures 1 through 16, 21-designates a relatively high structure, for example, a chimney, on which the automatic ascaffold, designated generally at Z2, is mounted.

The automatic scaffold apparatus 22 comprises a main support, designated at 23 in Figure 2, anda plurality of auxiliary supports V24 adaptedtobe spaced around the chimney 21 and being connected to the main support 2.3.in a manner presently to bedescribed.

The main support 23comprises a housing .25 having rigidly secured to its opposite sides respective vertical bars 26, 27 which lare rigidly connected at their lower ends by .a transverse bar 28. Rigidlysecured to the top` ends of the vertical bars 26 and 27 are the. outwardly extending horizontal bars 29 and 39 which are braced to the vertical bars 26 `and27 by suitable diagonal struts 31.

Each of the auxiliary supports 24-comprisesra vertical bar SZhaVingrigidly secured toits top end an .outwardly yextendinghorizontalbarza which isbraced to the vlower end .of the Ivertical barSZ-by-a diagonal str.ut.34,V as shown in 'Figure 3: Secured -to Ythe .inwardly facing.. portions of Vthelowerends .of-thevertical :bars-3.2 are. U-shaped .spacer brackets 35 adapted to abut the outersurfaceof thechimvrney..2.1 in .the mannershown inF-igure 3.1 Secured tothe top ends ofthe bars 32 andbeinginwardly directedfthere- .from .are :bracket members .36adapted to abut theouter lsurface of the Achimney -21 atlocations above and 'vertical- `l 1y. aligned Withthe associated .brackets 3'5.

Thervertical bars 26- and .27 of themain support .23are .provided .at their .lower .ends with abutment brackets .35, similar to those of :the auxiliarysupport 221'.V The housing 25.. is providedV .at .its .opposite .end rportions andfat its. frear `wall with f the inwardly directedabutment lugs [37,as

5 .shown-.in Figure-9, adaptedtoabutrthe outer surfacefof the chimney 1 V .substantially .in vertical rali'gnrnentwith andabove-.thelower-brackets35l Housing 25 is provided with the horizontallychannele'd Y rear .Wall .38r in .which is .slidably mounted laplfatemem- Y berv .39. Secured .on zthe 'plate .member.39 .is 4.an `arched .bracket 40 -having..one.:side thereof .engaged withtheend yof an abutment .rod .llslidably mounted .in th'esde-wall 431x015 ,-housing; and. biased into engagement .with the bracket [member A 40fby- .coiled springs 44- .bearing between they/all vRwanda washer 45 disposedon. the rod 41.*.and retained. thereonby anut'46. Journaledinthe housing 25, for example, in the bracket 40and in therear .wall'38 ofthe housing visV aLshaft47 on which is mounted a reel 48and a worm gear 49. A reversible electric. motor "50`is'm0untedon`the plate 38^andis dr'ivinjgly` coupled toV a"worm"51`^"meshing with worm gear 49",:1'as shown'in "Figure "8. Designated at SZisa limitrswitclitwhichfiis mounted on the side wall 43 of the housing 25 and which is provided with a pivoted actuating member 54 having a top arm portion extending in the path of movement of the slidable rod member 41, the actuating member 54 being biased counterclockwise, as viewed in Figure 8, toward a normally elevated position wherein the limit switch 52 is closed. The actuating member 54 is engaged by the end of the rod 41 responsive to the movement of plate member 39 to the right, as viewed in Figure 8, so that when said plate member reaches a predetermined position, the actuating member 54 is rotated clockwise, as viewed in Figure 8, and opens the limit switch 52, deenergizing the motor 50.

Designated at 55 is a cable which is connected at one end thereof to housing 25 adjacent the side wall 56 thereof, opposite side wall 43. rhe cable 55 is secured to the respective lug members 36 of the auxiliary supports 24, which are spaced around the chimney 21, and the end of the cable is secured to the reel 48, so that when the cable is wound up on the reel, said cable is ytightened by said reel and clampingly engages the outer surface of chimney 21.

As shown in Figure 7, the cable 55 extends slidably through arcuate sleeve members 56 rigidly secured to and projecting horizontally from the inner end portions of the respective abutment lugs 36, said sleeve members 56 being provided with anges 57 and 58. Retaining screws 59 extend through the anges 57 and are threadedly engaged in the flanges 58, whereby the cable 55 cannot disengage from the sleeves.

Cable 55 passes through an aperture 59 in side wall 43 and between a pair of guide rollers 60, 60 journaled in the housing 25 adjacent aperture 59, as shown in Figure 8. As will be readily apparent, when motor 50 is energized, the worm 51 drives worm gear 49 and shaft 4'7. In one direction of rotation of shaft 47 the cable 55 is wound up on the reel 48, causing the cable to be tightened. The tension in the cable moves the plate member 39 to the right, as viewed in Figure 8, until finally the bracket 40 engages abutment rod 41 and causes the limit switch 52 to open, which deenergizes the motor 50. Worm gear 49 meshing with worm 51 holds the reel 48 against reverse rotation, whereby the cable 55 is maintained in tension and secures the main support 23 and the auxiliary supports 24 to the chimney 21. However, by reversing the motor 50 by means of a suitable reverse energizing circuit, the cable may be loosened, as required.

Pivoted at 60 and 61 to the lower ends of the vertical bars 26 and 27 are respective sleeve members 62 and 63 which extend upwardly through suitable guide brackets 64 and 65 secured to the side walls 43 and 56 of housing 25. Slidably and non-rotatably disposed in the sleeve members 62 and 63 are respective externally threaded plungers 66 and 67. Secured to the -top ends of the sleeves 62 and 63 are respective gear housings 68 and 69 in which are rotatably mounted worm gears 70 threadedly engaged on the respective threaded plungers 66 and 67, as shown in Figure 12. The nut members 70 are rotatably supported in the housings 68 and 69 and are meshingly engaged by respective worms 71 journaled horizontally in said housings, as shown in Figure 11. The worms 71 are respectively coupled by exible shaft units 72 and 73 to the opposite ends of a drive shaft 74 rotatably mounted on lthe front wall 75 of the housing 25, as shown in Figure 2, for example, on bearing assemblies 76, 76.

A reversible electric motor 78 is mounted on the front wall 75 of housing 25 and is drivingly connected through a gear unit 79 to an 'output shaft 80. Shaft 80 is coupled by a belt 81 and suitable pulleys to the shaft 76, so as to be drivingly connected to the respective worms 71 to drive said worm simultaneously in the proper directions to either simultaneously raise or lower the respective threaded plunger members 66 and 67, said plunger members being raised or lowered by the rotation of the associated nut members 70, which are in turn meshingly en gaged by the respective worms 71.

As shown in Figure 13 a longitudinal key 82 is pro vided internally in each sleeve vmember 62 and 63 engaging slidably in a keyway in the associated plunger member to prevent rotation of the plunger member but to allow the plunger member .to move axially in the sleeve.

Additional sleeve members 83 are pivotally connected to the lower end portions of the respective vertical bars 32 of the auxiliary supports 24 and extend through U- shaped guide brackets 84 secured to the horizontal bar members 33 of the supports 24, as shown in Figures 4 and 16. Threaded plungers 85 are slidably but nonrotatably disposed within the sleeve members 83, in the same manner as explained in connection with the plungers 66 and 67, the auxiliary plungers 85 being threadedly engaged by worm gears rotatably mounted in gear housings 86 secured to the top ends of the sleeves 83. Respective worms meshingly engage said worm gears and are journaled horizontally in the gear housings 86, the worm shafts, shown at 87 in Figure 3, being interconnected by a flexible shaft 88 and being drivingly connected to a flexible shaft 89, shown in Figure 2, which is coupled to the output shaft of gear unit 79. Thus, the threaded plungers 66, 67 and 85 are simultaneously driven by the motor 78, said plungers being simultaneously raised or lowered, depending upon the direction of rotation of motor 78.

Secured to the top ends of the plungers 66 and 67 are respective bracket members 90 and 91, said bracket members being rigidly secured to the respective side walls 92 and 93 of an auxiliary reel housing 94 located above the main reel housing 2S. The reel housing 94 is provided with the channeled rear wall 95 in which is slidably mounted the plate member 96 on which is secured the arched bracket 97. A shaft 98 is journaled between the bracket 97 and the plate member 96 and has secured thereon the reel 98 and the gear 99. The gear 99 is meshingly engaged by a worm 100 coupled to the shaft of a reversible electric motor 101 mounted on plate 96. A push rod 102 is slidably mounted in the wall 92 and is `biased into engagement with the bracket 97 by a coiled spring encircling the same, as shown in Figure 8, similar to the spring 44 associated with the rod 41. A limit switch 104 is mounted on the side wall 92 and has 'an arm 105 engageable by the end of the push rod 102 to deenergize the motor 101 when plate member 96 is moved to the right a predetermined amount, as in the case of plate member 39 previously described.

Designated at 106 is a cable member having one end thereof connected to wall 93 at a lug 107 provided on said wall. Intermediate points on cable 106 slidably engage through sleeve members 56', which in turn are rigidly connected by bracket arms 107 to the top ends of the respective threaded plunger members 85. As shown in Figure 3, each arm 107 may be integrally formed with a sleeve portion 108 receiving the upper portion of the vassociated plunger 85 and may be clampingly secured to upper portion of the plunger by nuts 109. The arms 90, previously mentioned, are likewise formed with sleeve portions 108' which are clampingly secured to the top portions of the threaded plungers 66 and 67 by nuts 109', as is clearly shown in Figure 8.

The outer edges of the sleeve members 56 and 56 are parallel and are arcuate in shape, whereby said outer edg define arcuate slots 106 and 55 shown in dotted view in Figures 5 and 7. Said slots curve downwardly from the outer ends of the sleeves toward the midportions thereof, whereby the mid-portions of the slots are substantially at the bottoms of the sleeves. Thus, iuorder to insert'the cables in the sleeves, the cables must be loose and must be arcuately bent to pass through said slots. Similarly, the cables may be removed from the sleeves by disengaging them through said slots'without requiring the cables to be pulled entirely through the sleeves. The slots 106' and 55 'are' preferably ofr just suicient width to allow th'ecables to p ass therethrough', for example, are approximately` A: inch wide.

The end of cable r106 extends through an aperture110 insidewall "92'v and between guide rollers 111"journaled in the housing4 94'adjacent'said aperture.` The cable '6 is securedto andwound on 'the reel""98,' whereby said cable isztensioned byV therotation of .the reel 'to wind the cable up thereon, in the same manner-as described in connection with the cable 55. Thus, when' the motor 101`is energizedinits forward direction,the cable" 106 is fwoundlup on the reel'98 l'until a'li'miting tension is develope'dfinthe cable, at which pointthe limit'switch 104 opens the energizingcir'cuit of the motor, leaving the cable suiciently tight to clamp the top porti'onsofthe plungers 66,' 67 and'85 to therchimne'y 21"'above'the cable 55; Motor 101is provided"with' a suit'ablereverse energizing circuitwhich' may be. employed' to "reverse Ythe .direction 'of reel 98 and'to loosenthe'cable'106', when desired.'v

A's shown, the rear wall 9S' of the upperh'ousinge94l is provided 'with the inwardly directed' abutment 1ugs"112 en'gageable with the'outer surface' ofi'thechimneyZl'. The'arcuate'sleeve membersY 56 are integrally formed with the .arms 107, as above explained,A sothat tightening ofthe cable 106 kclamps thesleeves 56' tofth'echimn'ey surface, thusclampingly securingthetop ends' ofthe associated 'plungers 85`to said chimney surface.

VRigidlysecured toth'eouter' ends-'ofthe respective outwardly extending horizontal'v bar members 29'; 30 and`33 are'resp'ective verticalpost members 113;'"said post membershaving rigidly 'securedto their'top" ends the successive horizontally'elongated loop members-114 and115, shown in'Figures"14,15 and-15a.v

As'shown-in Figure 14, th'epost members 113 are adjustably 'secured lbyY meansv of vtop and bottom nuts116 and 117 engaged onV threaded lower portionsllS'provided onthe postmembers and yclampingly* securing the post members Y to the `associated outwardly extending lhorizontal 'bars 29, 30 and '33:

The loops 114 and 115 are welded together in-angularly spaced vertical planes which" intersect substantially coaxially with theA associated postwmembers 2113;v so 'as-to slidably receive railing rodsf119 therethroughfink th'e manner=clearly illustrated in Figure 1. Thefrailinglrods ^119`Jare` provided yatr their opposite ends @with Lenlarged `head portions- 120so that therods cannotfb'ecomedisengaged from the loops `114-and 11S, but mayf/slidably adjust themselves in saidloopsfin@ accordance with changesin the diameter l of the chimney f 21 `asthe scaf- .foldis raised or-lowered thereon.

Secured on the `horizontally` extending, outwardly projecting bar` members 29,? 30` and -33.'."are1 arched brackets 122 beneath. which are'disposed oor boards'123, said `-floor Y boards being thus supported! on the horizontal 'bar members. The end'portions of the flooriboards are providedwith-depending stoptpins 124 yi whichiare engageable withfthe supporting horizontal: bar members 29;"30l1and'33 to prevent the iloorvrboards fromislipping out from between the associated arched'retaining .brackets 122 and the subjacent horizontal supporting bars.

In operation; the scaffold is raised on-the-chimney 21 by rst tightening the lower cable 55 to clampingly secure the main support and 'the'auxiliary support to the outer'surface of--the-chimney. Themotor 78is then energized'v to raise theplunger members' 66,v 67 and 85 to-a substantial height, Thereafter,motorl78 is`v deenergized--fand the upper 'cable Y 106 istightened. The lower cable -55 is thenloosened and. motor- 7S` is' then operated-1inl a 'reversedirection; causinggthe sleeve vmembers 62,y 63 and-83 *toN -beelevated on-the plungerimembers 66, 67 and 85. After said sleeve members 62, 63 and 83 have been elevated for a substantial height, motor 78'- is deenergized and cable 55- is tightened. Cable 106 is then loosened and motor 78 is energized in its forward ,6 Y direction to elevate the plnger.memb`ers.66,l.67 fand 8S, thereafter repeating .the previously described... cycle .of operation, until the Vapparatus has.been. raise'dtoathe desired 'height on the chimney, f. l

Thescaold is lowered 'on lthe chimney by followinga procedure reverse to that abovedescribed..

.Figures 17, 18- and '19ill`ustrate a modiiication. of the invention wherein pneumatic means is employed vin place of delectric motors previously, vasthe dving vmeans' f for th'escafford apparatus. Thus, reversible airmotorslzt) maybe employed to drive the respective Acable reels,.for example, to drive the cable reel"98`in Figurey l.17,"fth`e motors y` operating thel wormsin the same manner as the reversible electric motors l'50 and 10'1"in the previously described 'form ofthe invention. Themain support, shown at 23', corresponding to the main sup.- port 23 in the previously described form ofthe invention, is provided'with elevating uidpressure cylinders 62' containingpistonsili having piston rods 64'- Iwhosetop end 'portions are connected by brackets 90" to the side walls ofthe upper reel iliousing, shown at 4921. VThe auxiliary supports are providedfwi'thsiniilar iiid pressure elevating cylinders .shown at 83 containing pistons 84""having1piston rods 285'. "The top ends'iof'thepiston ro`ds85 are connected by arms v107 to the cable sleeves receiving the cable 106, similar to thepreviouslyvdesc'ribed form' of theinvention. A suitable 'fluid pressure supply means is provided, connected `by` suitable control 'valves to the respective cylinders 62."and. 83 for simultaneously raising or loweringthe'pistons 63 and '84". Sadiiiid pressuremeansmay'also be'em'ployed bythe use of Isuitable reversing valves to operate the-fluid pressure'motrs 120.

In the 'form' of Ythe 'invention illustratedin 'Figure.20, instead of employing theexible shafts 72,73, 88an'd 89* to vdrivingly connect" the respective "'nut' members 70 to a Vsingleelectric motor 78, Aaseparate electric motor A is employed to drive each `of th'e'nut members indi'- vidually. Thus, as shown in Figure 20,' the motors .130 comprise reversibleelectrie'motors' which are connected inra series circuit to 'a common'current source', the circuit being provided'with suitableY reversing -swiches for reversibly applying current" to the series-connected motors. As shown, each motor 130is supportedbya suitable bracket'131' associated withand rigidly connected to'a gear housing, for example'the gear housing 68' ofthe main `support and the .gear housingsv 86`of.th'e auxiliary supports, wherebyy the motors 1304 are movable with Saidmain'support -andauxiliary supports.

While certain'specific embodiments of'an improved automatic, self-elevating scaffold apparatus lhave.' been disclosed in the'foregoing `description,"it will beunderstood Vthat various modifications within the spiritlofthe invention'may occur to those skilled in the art. Thereforefit `isinte`nded that no limitations be placed on the invention except asJdened by'the scope lofftheappended claims.

What is claimed is:

1. In an automatic self-elevating` scaffold apparatus foruse on chimneys or the like, a main support, arp1uralityof auxiliary supports adapted tobe spaced laround a`chimney, a first cable connected at .both ends tosaid main support and connected -at intermediateportions thereof to saidauxiliary supports so as to completely surroundllthe chimney, first cable-tightening meansconnected'to said tirs-t cable, respective vertically movable plungers slidably mounted v on said main ysupport vand said auxiliary supports, asecond cable locatedfabove the tirst cable and connected at both ends to said main sup: port and `connected at intermediate portions thereof to the top ends ofthe plungers so as'to also surround the chimney, second `cable-'tightening lmeans connected "to said second cable, reversible 'drivemeans, means driv inglyL connecting said' drive "means" to Asaid 'plungers `and being formed and arranged to at times elevate said.

plungers and second cable relative to the supports when the drive means operates in one direction and to lower the plungers and second 'cable -relative to the supports at other times when the drive means operates in a reverse direction, and scaffold-supporting means on said supports.

2. In an automatic self-elevating scalold apparatus for use on chimneys or the like, a main support, a plurality of auxiliary supports adapted to be -spaced around a chimney, a lirst cable connected at both ends to said main support and connected at intermediate portions thereof to said auxiliary supports so as to completely surround the chimney, rst cable-tightening means ou said main support connected to the end of said first cable, respective vertically movable plungers slidably mounted on said main support and said auxiliary supports, second cable-tightening means on the plunger associated with said main support, a second cable located above the first cable and connected at both ends to said main support and at intermediate portions thereof to the top ends of the plungers so as to also surround the chimney and connected to said second cable-tightening means, reversible drive means on said main support, means drivingly connecting said drive means to said plungers and 4being formed and arranged to at times elevate said plungers and second cable relative to the supports when the drive means operates in one direction and to at other times lower the plungers and second cable relative `to the supports when the drive means operates in a reverse direction, and respective outwandly extending platform-supporting arms rigidly secured to said supports.

3. In an automatic self-elevating scaffold apparatus for use on chimneys or the like,va main support, a plurality of auxiliary supports adapted to be spaced around a chimney, a first cable connected at both ends to said main support and connected at intermediate portions thereof to said auxiliary supports so as to completely surround the chimney, iirst cable-tightening means on said main support connected to the end of said iirst cable, respective vertically movable plungers slidably mounted on said main support and said auxiliary supports, second cable-tightening means on the plunger asso ciated with said main support, a second cable located above the irst cable and connected at both ends to said main support and -at intermediate portions thereof to the top ends of the plungers so as to also surround the chimney and connected to said second cable-tightening means, reversible drive means on said main support, means idrivingly connecting said drive means to said plungers and being formed and arranged to at times elevate said plungers and second cable relative tov-the supports when the drive means operates in one direction and to at other times lower the plungers and second cable relative to the supports when the drive means operates in a reverse direction, respective outwardly extending platform-supporting arms rigidly secured -to said supports, and respective platform elements disposed on said arms.

4. In an automatic self-elevating scalold apparatus for use on chimneys or the like, a main support, a plurality of auxiliary supports adapted -to be spaced around a chimney, a cable reel mounted on said main support, first drive means operatively connected to said reel, a first cable connected at one enld to said main support and at intermediate points thereon to said auxiliary supports so as to completely surround the chimney, the

other end of said cable being connected to said reel,`

vertical plungers slidably engaged with said supports, a second reel, means mounting said second reel on the top end of the plunger associated with said main support, second drive means operatively connected to said second reel, a second cable connected at one end to the top end of said last-named plunger and at its intermediate points thereon to the top ends of the remaining plungers so as to also surround the chimney, the other end of said seoond cable being connected to said second reel, third drive means on said main support, and means drivingly connecting said third drive means to said plungers and being formed and arranged to at times reversibly raise and lower said plungers and second cable relative to said supports.

5. In an automatic self-elevating scaffold apparatus for use on chimneys or the like, a main support, a plurality of auxiliary supports adapted to be spaced around a chimney, a cable reel mounted on said main support, first drive means operatively connected to said reel, a first cable connected at 'one end to said main support and at intermediate points thereon to said `auxiliary supports so as to completely surround the chimney, the other end of said cable being connected to said reel, respective threaded vertical plungers slidably and nonrotatably engaged with said supports, a second reel, means mounting said second reel on the top end of the plunger associated with said main support, second drive means operatively connected to said second reel, a second cable connected at one end to said last-named plunger and at intermediate points thereon to the top ends of the remaining plungers so as to also surround the chimney, the other end of said second cable being connected to said second reel, third drive means on said main support, respective nut members threadedly engaged on the plungers-'and drivingly engaging said supports, and means drivingly connecting said third drive means to said nut members and being formed and arranged to at times reversibly raise and lower said plungers and second cable relative to said supports.

' 6. In an automatic self-elevating scaffold apparatus for use on chimneys or the like, a main support, a plurality of auxiliary supports adapted to be spaced around a chimney, a cable reel mounted on said main support, rst drive means operatively connected to said reel, a first cable connected at one end to said main support and at intermediate points thereon to said auxiliary supports so as to completely surround the chimney, the other end of said cable being connected to said reel, respective threaded vertical plungers slidably and non-rotatably engaged with said supports, a second reel, means mounting said second reel on the top end of the plunger associated with said main support, second drive means operatively connected to said second reel, a second cable connected at one end to lthe top end of said last-named plunger and at intermediate points thereon to the top ends of the remaining plungers so as to also surround the chimney, the other end of said second -cable being connected to said second reel, third drive means on said main support, respective nut members threadedly engaged on the plungers and drivingly engaging said supports, means drivingly connecting said third drive means to said nut members and being formed and arranged to at times reversibly raise and lower said plungers and second cable relative to said supports, respective outwardly extending arms on said supports, and respective platform elements disposed on said arms.

References Cited in the tile of this patent UNITED STATES PATENTS 548,752 Gentry Oct. 29, 1895 784,606 Weightman Mar. 14, 1905 1,299,289 Berg Apr. 1, 1919 1,440,968 Chesebro Jan. 2, 1923 2,414,538 Lamb Jan. 2l, 1947 2,430,179 Lanchester Nov. 4, 1947 2,477,922 Emery et al. Aug. 2, 1949 FOREIGN PATENTS 368,920 France Oct. 24, 1906 

